JPS6225467B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a press molding die by overlaying a rough-processed base metal with a metal different from that of the base metal, in particular a press molding die having an approximately polygonal inner diameter profile. The present invention relates to a method for efficiently and easily producing a mold, and for obtaining an excellent mold.

Conventionally, the method of manufacturing this type of mold is to overlay metal with excellent wear resistance, seizure resistance, or slipperiness on the surface of steel materials using arc welding, gas welding, etc. In the case of gas welding, manual welding or automatic welding was used, and in the case of gas welding, overlay was performed exclusively by manual welding. Among these methods, when arc welding is used, the penetration in the welded part is large, so the component dilution between the base metal and the overlay metal becomes large.
Since the purity of the overlay metal is significantly reduced, its excellent properties such as wear resistance, seizure resistance, and sliding properties are lost. In order to avoid this, it is necessary to gradually increase the purity of the overlay metal by performing multi-layer overlay, and although the wear of the mold due to press working is extremely small, it is usually necessary to apply 3 to 4 layers of overlay. It didn't happen. Therefore, the time required for overlaying is long, and the original purpose of such a mold, which is to obtain a cheap and high-performance mold, is sometimes not achieved. In addition, in the case of gas welding, although it is possible to obtain high-quality build-up metal with small penetration in the weld, gas welding originally has the disadvantage that the amount of heat that can be input is small, so the welding speed is slow. .

Furthermore, dies whose inner diameter contour is roughly polygonal, such as rectangular drawing dies, have a roundness called a corner radius at the intersection of each side of the polygon, and a material to be formed from the top surface of the die to the inner surface of the die during press forming. The die shoulder has a roundness called a dial for sliding, and the intersection of this corner radius and the dial forms a saddle shape. However, if the die inner diameter contour is a polygon with a recess, the intersection of the corner radius and the dial of the recess becomes a part of the spherical shape or the like.

When overlaying such parts by arc welding, the quality of the overlay metal cannot be stabilized with manual welding, and automatic welding requires the use of expensive equipment such as copying equipment and numerical control equipment. It was hot.

This invention was made in view of the shortcomings of the conventional methods as described above. By using the reverse polarity soft plasma deposition method, welding with only one layer of deposition is possible, with almost no dilution of the components of the base material and the deposited metal. To provide a method for quickly manufacturing inexpensive and high-quality press-forming dies by processing grooves on the upper surface of the base metal only near rounded corners and overlaying the grooves only from the upper surface. It is something.

Examples of the present invention will be described below.
First, we will briefly explain the characteristics of the reverse polarity soft plasma build-up method. FIG. 1 compares the cross-sectional shapes of build-up beads in normal arc welding and reverse polarity soft plasma build-up. In the figure, 1 is an overlay, 2 is a penetration, and 3 is a base material. The dilution ratio expressed by the following formula is often used as a measure to express the characteristics of the built-up part.

Dilution rate (%) = Penetration cross-sectional area / Penetration cross-sectional area + Reinforcement cross-sectional area × 100 Figure 1 a shows the case of normal arc welding, but the dilution rate is several tens of percent. Compared to this, in the case of the reverse polarity soft plasma build-up method (Figure b), a low dilution rate of about 0.1% can be achieved. If this dilution rate is large, the overlay metal component will be diluted by the base metal and its properties will be significantly impaired, but this does not occur in the reverse polarity soft plasma overlay method. By the way, Figure 2 shows the result when a copper-aluminum alloy, which is commercially available as a material for molds and exhibits excellent wear resistance, seizure resistance, and slip resistance, is overlaid on SS41, an inexpensive and strong steel material. It shows the relationship between the Vickers hardness of overlay metal and the dilution rate. It can be seen that when the dilution rate increases even slightly, the hardness of the overlay metal decreases significantly.

In this way, metals with excellent properties as molds, such as the copper-aluminum alloys mentioned above, can be deposited on the surface of inexpensive and strong materials such as SS41 and S45C using the reverse polarity soft plasma deposition method. Once filled, it can be used as an excellent mold with just one layer of overlay.

This reverse polarity soft plasma build-up method has a much higher energy density than gas build-up, so it can build up with high efficiency, but automatic build-up is used to ensure stable and high-quality build-up. are doing. It is an object of the present invention to use this reverse polarity soft plasma build-up method to perform build-up with high efficiency and to easily obtain an excellent mold without using expensive equipment.

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 3 shows an example of the shape of the base metal to which the present invention is applied, and is a top view of the base metal that has been roughly machined to create a rectangular cylinder drawing die. 11 is a base metal, and 12 is a groove provided on the upper surface of the base metal 11 near a corner of the inner diameter contour.

The upper surface of the base metal 11 is rough-processed to remove an oxide film, etc., if necessary, and the inner diameter contour is cut out using a simple and highly efficient cutting method such as gas cutting. Also, at this time, the inner diameter contour near the corner portion is set inside the inner diameter contour of the finished die. Further, the depth of the groove 12 is cut to a depth that is at least equal to or greater than the depth dimension of the dial portion after processing with a die for press molding. As shown in FIG. 4, the groove 12 of the base metal 11, which has been roughly machined into such a shape, is first overlaid in one layer or in multiple layers depending on its depth, only from the top surface. In the figure, 13 is the groove 1 in Figure 3.
It is overlay metal that is overlaid on 2.

Thereafter, the inner surface of the base metal 11 is cut in consideration of the thickness of the build-up on the inner surface of the base metal 11 except for the vicinity of the corners. This state is shown in Figure 5, where the two-dot chain line indicates the state before cutting.
That is, the inner diameter contour in FIG. 4 is shown. Finally, as shown in Fig. 6, only one layer is added to the required part of the upper surface of the base metal 11 near the inner diameter contour and to a predetermined depth on the inner surface (a depth equal to or greater than the depth dimension of the dial on the shoulder of the die). After filling and finishing cutting, the rectangular tube re-drawing die is completed. In the figure, reference numeral 14 indicates metal build-up on the upper surface of the die, and reference numeral 15 indicates metal build-up on the dial portion of the inner surface of the die.

As the base metal, inexpensive and strong steel materials such as SS41 and S45C are suitable. Further, as the overlay metal, a copper-aluminum alloy having excellent wear resistance, seizure resistance, or slip property is suitable. Copper-aluminum alloys have a lower melting point than steel materials, which have excellent properties as molds, so it is easier to apply high-quality overlay with a small dilution ratio.
Moreover, since it can be cut, finishing processing is easy.

In the above embodiment, a method for manufacturing a rectangular tube drawing die was described, but the present invention can be applied to any press forming die whose inner diameter contour is roughly polygonal, consisting of straight lines and rounded corners. In addition, although we have shown examples of copper-aluminum alloys as overlay metals, there are other
Any metal with excellent wear resistance, seizure resistance, or slip properties may be used.

As described above, according to the present invention, when manufacturing a press-forming die with an inner contour of a substantially polygonal line and rounded corners by overlaying a metal different from the base metal onto the surface of the base metal, it is possible to improve the durability. A metal with excellent wear resistance, seizure resistance, and slip properties is overlaid using the reverse polarity soft plasma overlay method, and at this time, only around the corner radius of the inner diameter contour is overlayed from the top surface into the groove provided in the base metal. For other parts, only one layer of overlay is applied from the top and inner surfaces, so there is no need to use high-value equipment such as copying equipment or numerical control equipment for overlaying, and press forming is extremely efficient and has excellent performance. You can make open dice.

[Brief explanation of the drawing]

Figure 1 is a diagram comparing the cross-sectional shapes of a conventional method and a reverse polarity soft plasma build-up bead. Figure 2 is a cross-sectional view showing the overlay bead in the method. Figure 2 is a diagram showing the relationship between the Vickers hardness of the overlay metal and dilution rate when copper-aluminum alloy for molds is overlaid onto the surface of SS41 material. Figure 3 is a diagram showing the relationship between the Vickers hardness of the overlay metal and the dilution rate. 1 is a plan view showing an example of the shape of the base metal used in the present invention, and FIGS. 4 to 6 are plan views showing an example of the manufacturing procedure of the press molding die in the present invention. 1... Surplus, 2... Penetration, 3... Base material, 11
... Base metal, 12... Groove, 13... Overlay metal built up in groove 12, 14... Overlay metal on the upper surface of the die, 15... Overlay metal on the dial part on the inner surface of the die. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. A press-forming die whose inner diameter contour consists of straight lines and rounded corners, and in which a metal different from the base metal is overlaid on the upper surface and inner surface of the roughly processed base metal near the inner diameter contour. In the manufacturing method, a reverse polarity soft plasma build-up method is used as a build-up method, and the depth dimension of the dial of the die shoulder that continues from the top surface of the die to the inner surface is applied to the top surface of the base metal only near the rounded corners. A method of manufacturing a die for press forming, characterized by machining a groove with a depth equal to or greater than , and overlaying the groove only from the upper surface. 2. The method for manufacturing a press-forming die according to claim 1, wherein a copper-aluminum alloy is used as the overlay metal. 3. The method of manufacturing a press-forming die according to claim 1, characterized in that a metal having better wear resistance, seizure resistance, or slipperiness than the base metal is used as the overlay metal. 4. The method for manufacturing a press-forming die according to claim 1, characterized in that only one layer of overlay is applied to the base metal except near rounded corners.